Fuzzy Similarity in Species Distributions
fuzzySim can convert binary presence-absence to fuzzy occurrence data, using e.g. trend surface analysis, inverse distance interpolation or prevalence-independent environmental favourability modelling, for one or more species simultaneously.
It can then calculate e.g. fuzzy change and fuzzy similarity among (fuzzy) species distributions and/or among (fuzzy) regional species compositions, avoiding the use of thresholds and instead using fuzzy logic versions of known similarity indices.
'fuzzySim' was created long before I knew GitHub, and it's still maintained on its original platform, R-Forge. So, you can install the development version with:
install.packages("fuzzySim", repos="http://R-Forge.R-project.org")
The package is also on CRAN, but the development version (above) often includes recent enhancements and small bug fixes.
Find out more about the package, along with usage manuals and literature examples, at https://fuzzysim.r-forge.r-project.org/